How losing weight 'empowers' film stars – and brides

Hollywood stars lose weight for a role, as it shows their commitment to the part. Could that be the same reason so many British brides go on a pre-wedding diet?

'Actors change their bodies because it’s the one part of the job they believe they have complete control over': Eva Wiseman on the phenomenon of actors losting weight for parts. Above: Anne Hathaway. Photograph: Getty

To win an Oscar, actors often have to lose a bit of themselves. The meat around their hips, frequently, and the flesh under their chin. The 25lb Anne Hathaway lost – sorry, hang on – "lost" is the wrong word; it implies carelessness. The 25lb she sent away, like old dogs to a farm. The pounds she aborted, burned, shrank for the part in Les Misérables that last month won her an award for best supporting actress, the pounds she excreted by eating only, she told Vogue, "two thin squares of dried oatmeal paste a day", showed her commitment to the role. And this commitment to the role, in part, won her the award.

Actors change their bodies because it's the one part of the job they believe they have complete control over. The acting itself, they have little power to change – it flows through them like a bad mood. But the way they look they can mould, sculpt – they can have low-calorie meals delivered by courier every morning, a personal trainer living on set, or they can take pills (Grazia this week reports on the "new £13 diet pill that's got Hollywood hooked"). Equally they can "bulk up" on bread for small-town realism and pump up their arms to become postmodern superheroes.

They can work with a dedicated team to build the body their character might inhabit, and this transformation becomes one of the key stories they tell in the film's publicity drive. They will sit with a green tea upstairs at Claridge's and discuss juice fasts and red meat, or in the case of Matthew McConaughey, who lost 40lb to play a man with HIV in the film Dallas Buyers Club, "fresh fish… small amounts. If anything," he said, "it's as much a spiritual journey as it is physical."

For the women, weight gain wins them plaudits, as it shows a lack of vanity, and weight loss is seen as covetable, so interviews focus on how they got there for dieting readers's reference. But for the men, we demand details of their spiritual journey. We ask why – why, man, would you want there to be less of you?

Outside of Hollywood, the real-life equivalent of fasting for a role is the pre-wedding diet. Both involve shedding weight for a single photo call; both require you to change your appearance to show your commitment to the part. More than five million women in the UK lose weight before their wedding; over the course of a short engagement, one in 10 loses more than 4st. And the Harley Medical Group reports a 13% rise year-on-year in bookings for pre-wedding surgery – brides make up 30% of cosmetic surgeons' clientele, booking wrinkle fillers, veneers, breast implants, and hand lifts for close-up shots of the ring. They are changing their bodies to fit their dresses.

I know I'm not alone in finding this disturbing – I know it's none of my business, really, what my peers do with their bodies. And I know, too, that as the pressure to host an extravagant wedding grows and anxiety builds, like actors on set, brides feel as though their bodies in the wedding photo are one of the few things they have power over. But these moments are meant to be celebratory – the camera is there to document the occasion rather than be the occasion.

It comes from a glossy place, this belief that you should strive for perfection, a place scented with perfume samples where flaws are stories. Everything that's unhealthy about the weight-loss industry is present in the Oscar diets – the quick drop, the cognitive eating, the control and dampening of desire, all of which trickles down to the trend for wedding-day fasts. But, especially on a day designed to celebrate you, especially when they're holding a glass of cava, your friends will not draw circles around your upper arms or judge the quality of your skin. The beauty of not being a celebrity, and sometimes we forget this, is that you're not a celebrity.